Natural History of Asymptomatic Superior Mesenteric Arterial Stenosis Depends on Coeliac and Inferior Mesenteric Artery Status.

OBJECTIVE: The benefit of preventive treatment for superior mesenteric artery (SMA) stenosis remains uncertain. The latest European Society for Vascular Surgery (ESVS) guidelines remain unclear given the lack of data in the literature. The aim of this study was to evaluate asymptomatic SMA stenosis prognosis according to the presence of associated coeliac artery (CA) and/or inferior mesenteric artery (IMA) stenosis. METHODS: This was a single academic centre retrospective study. The entire computed tomography (CT) database of a single tertiary hospital was reviewed from 2009 to 2016. Two groups were defined: patients with isolated > 70% SMA stenosis (group A) and patients with both SMA and CA and/or IMA > 70% stenosis (group B). Patient medical histories were reviewed to determine the occurrence of mesenteric disease (MD) defined as development of acute mesenteric ischaemia (AMI) or chronic mesenteric ischaemia (CMI). RESULTS: Seventy-seven patients were included. Median follow up was 39 months. There were 24 patients in group A and 53 patients in group B. In group B, eight (10.4%) patients developed MD with a median onset of 50 months. AMI occurred in five patients with a median of 33 months and CMI in three patients with a median of 88 months. Patients of group B developed more MD (0% vs. 15.1%; p = .052). The five year survival rate was 45% without significant difference between groups. CONCLUSION: Patients with SMA stenosis associated with CA and/or IMA seem to have a higher risk of developing mesenteric ischaemia than patients with isolated SMA stenosis. Considering the low life expectancy of these patients, cardiovascular risk factor assessment and optimisation of medical treatment is essential. Preventive endovascular revascularisation could be discussed for patients with non-isolated > 70% SMA stenosis, taking into account life expectancy.

A simple coronary blood flow model to study the collateral flow index.

In this work, we present a novel modeling framework to investigate the effects of collateral circulation into the coronary blood flow physiology. A prototypical model of the coronary tree, integrated with the concept of Collateral Flow Index (CFI), is employed to gain insight about the role of model parameters associated with the collateral circuitry, which results in physically-realizable solutions for specific CFI data. Then, we discuss the mathematical feasibility of pressure-derived CFI, anatomical implications and practical considerations involving the estimation of model parameters in collateral connections. A sensitivity analysis is carried out, and the investigation of the impact of the collateral circulation on FFR values is also addressed.

Mesenteric Arteriovenous Dysplasia/Vasculopathy Mimicking Crohn's Disease: A Case Report / Displasia arteriovenosa mesentérica/vasculopatía mimetizante de enfermedad de Crohn: reporte de un caso

Mesenteric arteriovenous vasculopathy (MAVD/V) is an extremely rare and poorly understood disease and its incidence is probably underestimated. It is an uncommon, non-inflammatory and non-atherosclerotic form of mesenteric vascular injury, first reported in 2016, with characteristic histopathologic evidence of fibromuscular dysplasia-like vascular changes. We present the case of a chronically ill 84-year-old female with a 5 year history of recurrent small bowel obstruction, who underwent segmental resection of the small bowel. Intraoperative examination showed bowel stricture with fibrosis, intraluminal pill fragments and creeping mesenteric adipose tissue clinically compatible with Crohn's disease. Histological examination showed acute and chronic mucosal injury characterized by crypt distortion, ulcerations with granulation tissue, pseudo-pyloric metaplasia, areas of fibrosis and serosal adhesions. Multiple blood vessels (including both veins and arteries) demonstrated wall hyalinization, elastic degeneration and non-atherosclerotic luminal occlusion. The pattern of the mucosal injury is, in this case, potentially a consequence of acute and chronic ischemic processes secondary to mesenteric arteriovenous vasculopathy

La vasculopatía arteriovenosa mesentérica (MAVD/V) es una enfermedad extremadamente rara y poco conocida, con una incidencia probablemente subestimada. Se trata de una forma infrecuente, no inflamatoria y no aterosclerótica de lesión vascular mesentérica, reportada por primera vez en 2016, con evidencia histopatológica característica de cambios vasculares de tipo displasia fibromuscular. Presentamos el caso de una paciente crónica de 84 años de edad, con historia de cinco años de obstrucción recurrente de intestino delgado a quien se le practicó resección segmental del mismo. El examen intraoperatorio reveló estenosis intestinal con fibrosis, fragmentos intraluminales de píldoras, y tejido adiposo mesentérico serpiginoso clínicamente compatible con enfermedad de Crohn. El examen histológico reveló lesión mucosa aguda y crónica, evidenciada por distorsión de la cripta, ulceraciones con tejido granuloso, metaplasia pseudopilórica, áreas de fibrosis y adherencias serosas. Los múltiples vasos sanguíneos (incluyendo venas y arterias) reflejaron hialinización de la pared, degeneración elástica y oclusión luminal no aterosclerótica. El patrón de la lesión mucosa es, en este caso, una consecuencia potencial de un proceso isquémico crónico secundario a vasculopatía arteriovenosa mesentérica

Vascular Calcifications are Associated with Increased Mortality in Patients with Acute Mesenteric Ischemia.

BACKGROUND: Vascular calcifications have been identified as predictors of mortality in several cardiovascular diseases but have not been investigated in context of acute mesenteric ischemia. The aim of this study was to investigate the impact of vascular calcifications in patients with acute mesenteric ischemia. METHODS: Patients admitted for an acute mesenteric ischemia were retrospectively included. The presence of calcifications in the visceral aorta, the celiac trunk, the superior mesenteric artery, and the renal arteries was assessed on computed tomography scan images at the arterial phase. The calcification volumes were measured using the software Aquarius iNtuition Edition®. RESULTS: The all-cause mortality was 55 out of 86 patients (63.9%) for a median follow-up of 3.5 days (1-243). The survival rate of patients with calcification in the superior mesenteric artery was significantly lower than that of those without calcification (22% vs. 55.6%, P = 0.019). Patients who died had significantly a higher frequency of calcifications in the superior mesenteric artery, the visceral aorta, the celiac trunk, and the renal arteries. CONCLUSIONS: The presence of vascular calcifications in the superior mesenteric artery is associated with increased mortality in patients diagnosed with acute mesenteric ischemia. Further studies are required to identify the mechanisms underlying this association.

Mesoportal bypass, interposition graft, and mesocaval shunt: Surgical strategies to overcome superior mesenteric vein involvement in pancreatic cancer.

BACKGROUND: In pancreatic cancer, extensive tumor involvement of the mesenteric venous system poses formidable challenges to operative resection. Such involvement can result from cavernous collateral veins leading to increased intraoperative blood loss or long-segment vascular defects of not only just the superior mesenteric vein but also even jejunal/ileal branches. Strategies to facilitate margin-free resection and safe vascular reconstruction in pancreatic surgery are important, particularly because systemic control of the tumor is improving with multi-agent chemotherapy regimens. METHODS: We describe a systematic, multidisciplinary assessment for patients with pancreatic cancer that involves the superior mesenteric vein, as well as the preoperative planning of those undergoing operative resection. In addition, detailed descriptions of operative approaches and technical strategies, which evolved with increasing experience at a high-volume center, are presented. RESULTS: For the preoperative evaluation of tumor-free, vascular locations for potential reconstruction and collateralization, computed tomographic imaging with high-resolution of vascular structures (used with 3-dimensional or cinematic rendering) allows a precise calibration of radiographic data with intraoperative findings. From an operative perspective, we identified 5 potential strategies to consider for resection: collateral preservation, mesoportal bypass (preresection), mesoportal interposition graft (postresection), mesocaval shunt, and various combinations of these strategies. Many of these techniques use interposition grafts, making it essential to assess autologous veins (preferred conduit for reconstruction) or to prepare cryopreserved vascular allografts (an alternative conduit, which must be thawed and should be matched for size and blood type). CONCLUSION: Herein we share operative strategies to overcome involvement of the superior mesenteric vein in pancreatic cancer. Improvements in preoperative planning and operative technique can address common barriers to resection with curative intent.

Quantitative evaluation of superior mesenteric artery calcification in hemodialysis patients undergoing aortic valve replacement.

OBJECTIVE: Postoperative acute mesenteric ischemia (AMI) in the long-term hemodialysis (HD) patients could be a disastrous complication leading to high mortality. The objective is to evaluate the association between the presence of superior mesenteric artery calcification (SMAC) and early and late outcomes after aortic valve replacement (AVR) in HD patients. METHODS: Between April 2003 and December 2018, the enrolled 46 HD patients (19 women; mean age 72 years) who underwent AVR for severe aortic valve stenosis were retrospectively reviewed. 25 patients (54.3%) who had severe calcifications of superior mesenteric artery (SMA) were defined as the SMAC group, and the calcification extent of SMA was evaluated on preoperative non-contrast CT using Agaston calcium score [calcification area (cm2) × max CT value (HU)]. The operative outcomes were compared with those of the non-SMAC group comprising 21 patients (45.7%). RESULTS: The following factors in SMAC group were statistically higher compared with those of the non-SMAC group: age (73.6 ± 7.2 vs 69.3 ± 7.1 years; p = 0.04), celiac artery calcification (76.4% vs 17.6%; p < 0.001), calcium score of SMA (692.3 ± 300.0 vs 123.5 ± 180.7; p < 0.001), the incidence of AMI (24.0% vs 4.7%; p = 0.001), and hospital mortality (16.0% vs 0%; p = 0.02). In multivariate analysis, the presence of SMAC was significantly associated with AMI (OR 3.8, p = 0.05) and hospital mortality (OR 2.4, p = 0.02). Calcium score of SMA in patients complicated with AMI was significantly higher than those without AMI (815.7 ± 300.5 vs 366.9 ± 351.2; p < 0.01). CONCLUSION: Quantitative evaluation of SMAC could be a predictive marker of incidence of AMI after AVR in HD patients.

Simultaneous treatment of ischaemic bowel and ischaemic stroke with intravenous thrombolysis therapy.

Novel treatment of simultaneous mesenteric and cerebral ischaemia with systemic thrombolysis. A 75-year-old man presented to the acute stroke team with aphasia, right-sided weakness and distressed with a pain he was unable to localise. He was treated with intravenous thrombolysis with tissue plasminogen activator for a left middle cerebral artery stroke. Decompensation on the ward during thrombolysis with worsening abdominal distension and pain, hypotension and tachycardia prompted a CT angiogram scan, which displayed proximal inferior mesenteric artery occlusion. Thrombolysis treatment resulted in excellent improvement of both his dysphasia and weakness from the left cerebral ischaemic stroke and reperfusion of the ischaemic bowel, without surgical intervention.

Use of long saphenous vein graft in acute on chronic mesenteric ischaemia.

Acute mesenteric ischaemia is a relatively rare surgical emergency, but despite advances in diagnostic tests, the mortality of this condition remains stubbornly high (50%-80%). This is principally because of the non-specific nature of the presenting symptoms and subsequent delay in diagnosis. We report an unusual case of acute mesenteric ischaemia treated by emergency laparotomy, small bowel resection and revascularisation using reversed long saphenous vein graft.

Mesenteric ischemia-reperfusion: an overview of preclinical drug strategies.

Mesenteric ischemia is a surgical emergency caused by a transient reduction in blood perfusion to the bowel. Despite accounting for only 0.1% of hospital admissions and 1-2% of gastrointestinal diseases, its elusive symptoms often lead to dramatically high morbidity and mortality rates. The complex cascade of inflammatory events and mediators triggered by mesenteric ischemia-reperfusion (I/R) accounts for the plethora of proposed pharmacological targets and for the current lack of an efficacious drug strategy for its management. It is hoped that a deeper understanding of its pathogenesis and the preclinical therapeutic strategies identified to date and described herein will improve the translation into the clinical setting of the pharmacological armamentarium against a life-threatening disorder that is currently mainly managed surgically.

Neutrophil-to-Lymphocyte Ratio and Platelet-to-Lymphocyte Ratio Are Effective Predictors of Prognosis in Patients with Acute Mesenteric Arterial Embolism and Thrombosis.

BACKGROUND: The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) have been shown to be valuable prognostic markers for a variety of pathological conditions including solid tumors, sepsis, and others. However, the prognostic values of the NLR and PLR in patients with acute mesenteric arterial embolism (AMAE) and acute mesenteric arterial thrombosis (AMAT) have not been elucidated. The aim of this study was to determine the predictive value of the NLR and PLR for poor prognosis in patients with AMAE and AMAT. METHODS: A total of 137 patients with AMAE (n = 77) or AMAT (n = 60) were divided into a poor outcome group (cases of intestinal necrosis or death) and a better outcome group (cases without intestinal necrosis who survived successfully), according to prognosis. Neutrophil, platelet, and lymphocyte counts were recorded before pharmacotherapy or surgery. The NLR and PLR were calculated, and logistic regression analysis was performed to test their prognostic values. RESULTS: The cutoff values for NLR and PLR were 11.05 and 156.26, respectively. The PLR was linearly associated with the NLR (R = 0.769, P < 0.001). NLR (odds ratio [OR] = 6.835, 95% confidence interval [CI] = 2.282-20.469, P = 0.001), PLR (OR = 4.871, 95% CI = 1.627-14.587, P = 0.005), and coronary heart disease (OR = 3.388, 95% CI = 1.156-9.929, P = 0.026) were found to be independent prognostic factors for the patients. CONCLUSIONS: NLR ≥ 11.05, PLR ≥ 156.26, and coronary heart disease were shown to be risk factors for poor prognosis in patients with AMAE and AMAT. According to these factors, patients can be divided into 3 prognostic groups: good, NLR < 11.05 with PLR < 156.26; moderate, NLR < 11.05 with PLR ≥ 156.26 or NLR ≥ 11.05 with PLR < 156.26; and poor, NLR ≥ 11.05 with PLR ≥ 156.26.

Fatal Acute Hemorrhagic Bowel Infarction Caused by Mesenteric Venous Thrombosis.

Acute mesenteric venous thrombosis (MVT) is a rare, but life-threatening medical phenomenon. MVT is normally characterized by insidious onset, with nonspecific signs and symptoms. A high index of clinical suspicion is required for diagnosis, and emergency surgery is necessary to optimize the chances of patient survival, especially in the people aged more than 70 years. Surprisingly, based on my review of the literature, no fatal acute MVT case has been reported in the forensic literature. All reported such cases have been documented in medical literature, and most of them have been associated with underlying risk factors for venous thrombosis, such as hypercoagulable state, certain cancers, and stasis of the blood flow. Here, I report the case of a sudden unexpected death due to extensive intestinal ischemia and infarction with massive abdominal hemorrhage caused by acute MVT in a 72-year-old man without known underlying risk factors.

Idiopathic Myointimal Hyperplasia of Mesenteric Veins: An Uncommon Cause of Ischemic Colitis With Distinct Mucosal Features.

Idiopathic myointimal hyperplasia of mesenteric veins causes chronic ischemic mucosal injury with segmental strictures that mimic inflammatory bowel disease and nonocclusive ischemic colitis. It is characterized by myointimal proliferative changes that narrow the lumina of veins combined with ischemic injury and ulcers. Most cases reported to date have been diagnosed following surgical resection. The aim of this study was to determine whether mucosal changes of idiopathic myointimal hyperplasia of mesenteric veins are sufficiently sensitive and specific to allow its recognition in biopsy material. The study group consisted of 10 patients with idiopathic myointimal hyperplasia of mesenteric veins who underwent surgical resection of the affected colon, 7 of whom had available prior endoscopic biopsies. The control group included 10 patients each with radiation, nonocclusive ischemia, Crohn disease, diverticulitis, and mucosal amyloidosis, and 5 cases of small vessel (leukocytoclastic) vasculitis. Study patients were mostly older men with distal colorectal disease. All resection specimens showed mucosal ischemia with numerous thick-walled (arteriolized) capillaries and glassy subendothelial fibrin deposits; numerous hyalinized, eosinophilic thrombi were detected in 90% of colectomy specimens. Biopsies showed arteriolized capillaries (100%), subendothelial fibrin deposits (86%), fibrin thrombi (43%), and perivascular hyalinization (43%). Fibrin thrombi were observed in only one case each of ischemic colitis and small vessel vasculitis, and none of the other abovementioned features were seen in any of the controls. We conclude that arteriolized capillaries, subendothelial fibrin deposits, and perivascular hyalinization are frequent and specific features that can facilitate recognition of idiopathic myointimal hyperplasia of mesenteric veins in biopsy samples.

Mesenteric Arteriovenous Dysplasia/Vasculopathy Is Distinct From Fibromuscular Dysplasia.

Fibromuscular dysplasia (FMD) is a noninflammatory, nonatherosclerotic vasculopathy that usually affects the carotid and renal arteries. We have observed FMD-like vascular changes in specimens resected for ischemia or Crohn's disease (CD). On the basis of a systematic clinicopathologic review of these 11 cases identified between 1982 and 2014, we describe a distinct mesenteric vasculopathy that involves both arteries and veins [mesenteric arteriovenous dysplasia/vasculopathy (MAVD/V)] and is characterized by (1) concentric/eccentric smooth muscle collarette around the tunica media of both the artery and the vein in ≥2 foci, (2) varying degrees of intimal and medial hyperplasia and adventitial fibrosis, and (3) lack of inflammation or thrombi. MAVD/V cases were clinically diagnosed as CD (45%), mass/lesion (27%), ischemia (9%), obstruction (9%), or rectal prolapse (9%). Abdominal pain for >1 year was the most common symptom. Most patients were women (M:F=1:2.7; mean age, 63 y). Mucosal changes mimicking CD, such as architectural distortion (55%), multifocal ulcers (73%), and pyloric gland metaplasia (64%), were common; however, no granulomas or transmural lymphoid aggregates were identified. Ischemic pattern of injury was seen in 4 cases. Upon follow-up (mean, 31.2 mo), 8 patients were found to be asymptomatic, 2 had died of unrelated causes, and 1 was lost to follow-up. We propose the name MAVD/V for a distinct noninflammatory, nonatherosclerotic, localized form of mesenteric vasculopathy that involves both arteries and veins, distinct from FMD. Unlike FMD, surgical resection appears to be curative, with a favorable clinical outcome. Awareness of this vascular entity is important as patients may be potentially misdiagnosed as having CD and ischemic bowel disease.

Endothelial Cell-Derived von Willebrand Factor Is the Major Determinant That Mediates von Willebrand Factor-Dependent Acute Ischemic Stroke by Promoting Postischemic Thrombo-Inflammation.

OBJECTIVE: von Willebrand factor (VWF), which is synthesized in endothelial cells and megakaryocytes, is known to worsen stroke outcome. In vitro studies suggest that platelet-derived VWF (Plt-VWF) is biochemically different from the endothelial cell-derived VWF (EC-VWF). However, little is known about relative contribution of different pools of VWF in stroke. APPROACH AND RESULTS: Using bone marrow transplantation, we generated chimeric Plt-VWF mice, Plt-VWF mice that lack ADAMTS13 in platelets and plasma (Plt-VWF/Adamts13(-/-)), and EC-VWF mice to determine relative contribution of different pools of VWF in stroke. In brain ischemia/reperfusion injury model, we found that infarct size and postischemic intracerebral thrombo-inflammation (fibrin(ogen) deposition, neutrophil infiltration, interleukin-1ß, and tumor necrosis factor-α levels) within lesions were comparable between EC-VWF and wild-type mice. Infarct size and postischemic thrombo-inflammation were comparable between Plt-VWF and Plt-VWF/Adamts13(-/-) mice, but decreased compared with EC-VWF and wild-type mice (P<0.05) and increased compared with Vwf(-/-) mice (P<0.05). Susceptibility to FeCl3 injury-induced carotid artery thrombosis was comparable between wild-type and EC-VWF mice, whereas Plt-VWF and Plt-VWF/Adamts13(-/-) mice exhibited defective thrombosis. Although most of the injured vessels did not occlude, slope over time showed that thrombus growth rate was increased in both Plt-VWF and Plt-VWF/Adamts13(-/-) mice compared with Vwf(-/-) mice (P<0.05), but decreased compared with wild-type or EC-VWF mice. CONCLUSIONS: Plt-VWF, either in presence or absence of ADAMTS13, partially contributes to VWF-dependent injury and postischemic thrombo-inflammation after stroke. EC-VWF is the major determinant that mediates VWF-dependent ischemic stroke by promoting postischemic thrombo-inflammation.

[SURGICAL TREATMENT OF AN ACUTE MESENTERIAL ISCHEMIA].

Experience of surgical treatment of 143 patients, suffering an acute mesenterial ischemia, was summarized. Isolated intestinal resection was performed in 41 patients (lethality 65.9%), intestinal resection with the mesenterial vessels thrombembolectomy--in 9 (lethality 33.3%). After performance of the combined intervention postoperative lethality was in two times lower, than after isolated intestinal resection.

A Case of Idiopathic Mesenteric Phlebosclerosis with Progressive Intestinal Necrosis.

The patient was a 39-year-old woman who was referred to our department from her previous doctor with a 2-day history of right abdominal pain. Abdominal computed tomography showed wall thickening associated with calcification in the ascending colon. Contrast enhancement in the same portion of the intestinal wall was rather poor. Fluid accumulation was also seen around the intestine, so emergency surgery was performed under a provisional diagnosis of intestinal necrosis. Intestinal necrosis due to idiopathic mesenteric phlebosclerosis was diagnosed from postoperative histopathological tests. Idiopathic mesenteric phlebosclerosis displays a chronic course and in most cases conservative treatment is indicated. Bowel obstruction is common among patients who require surgical treatment, but rare cases such as the present one are also seen in which intestinal necrosis occurs. In recent years, an association with herbal medicine has been indicated as one potential cause of this disease, and this entity should be kept in mind when patients with acute abdomen and a history of taking herbal medicines are encountered.

[THROMBOANGIITIS OBLITERANS OVERLAPPING WITH ATHEROSCLEROTIC OCCLUSIVE ARTERIAL DISEASE: SMALL MESENTERIC ARTERY INVOLVEMENT BY THROMBOANGIITIS OBLITERANS].

INTRODUCTION: Thromboangiitis obliterans is an inflammatory occlusive vascular disease of young smokers that commonly involves the small and medium sized arteries and veins of the extremities. An important differential diagnosis of thromboangiitis obliterans is atherosclerotic arterial disease. An atypical presentation of thromboangiitis obliterans by involvement of mesenteric arteries has been described sporadically. CASE PRESENTATION: We report the case of a patient presenting with Raynaud's phenomenon, ischemia of the upper and lower extremities, as well as mesenteric ischemia. The dramatic course of the disease advanced to gangrene of the calves and intestinal infarction. In this patient, angiographic and histologic features were consistent with thromboangiitis obliterans associated with atherosclerotic arteriopathy. DISCUSSION: A review of the literature revealed 31 reported cases of mesenteric artery involvement by thromboangiitis obliterans. The overlap between thromboangiitis obliterans and atherosclerotic arteriopathy is rare but has recently focused attention in the literature. CONCLUSION: In the differential diagnosis of mesenteric ischemia, thromboangiitis obliterans is a rare but important diagnosis that should be considered. In view of shared features of thromboangiitis obliterans and peripheral artery disease, awareness of their possible coexistence is needed in order to make the right diagnosis and offer proper treatment.

Embolic superior mesenteric artery (SMA) occlusion secondary to a cardiac sarcoma.

We present a case of embolic acute mesenteric ischaemia (AMI) secondary to an underlying cardiac sarcoma, an exceedingly rare presentation only reported twice before. A 46-year-old man presented to accident and emergency department during the night with severe abdominal pain and vomiting. An urgent CT angiograph demonstrated superior mesenteric artery (SMA) occlusion with ischaemic small bowel. Joint surgical effort from vascular and general surgeons successfully recanalised the SMA and a 20 cm segment of small bowel was resected. Postoperatively, an echocardiogram demonstrated a mass within the left atrium. After cardiothoracic resection, the mass was found to be a rare undifferentiated cardiac sarcoma. Further staining on the embolus retrieved from the SMA revealed scattered spindle cells with a similar immunohistochemistry profile to that of the resected cardiac sarcoma. The patient was subsequently discharged well on lifelong warfarin.